First report of Diplostomidae metacercariae (Trematoda: Digenea) in African catfish Clarias gariepinus (Siluriformes: Clariidae) in Brazil

Abstract

Clarias gariepinus is a fish from North of South Africa and was later introduced in several countries, including Brazil. The present study aimed to describe the first report of Diplostomidae metacercariae in C. gariepinus in Brazil. For this, 30 C. gariepinus were captured in a lake in the city of Campos dos Goytacazes, RJ, Brazil. Fishes were euthanized using freezing and necropsied for collection of parasites. The organs were dissected and analyzed for the presence of parasites that were processed for light and scanning electron microscopy. Trematodes were stained with Semichon’s Carmine and Gomori’s Trichrome, observed and schematized under a light microscope with image analysis software. A total of 190 trematodes were collected from the gills, suprabranchial organs, heart, stomach, intestinal mesentery, liver and body cavity of the fish. The parasites had a foliaceous body divided by a discrete constriction, without genital primordia, and a holdfast organ present at the posterior region, typical of metacercariae of the family Diplostomidae. It was classified as the 'Diplostomulum' morphotype, based on the morphology of the reserve bladder structure. This is the first report of the metacercariae of Diplostomidae parasitizing C. gariepinus in the Americas. This fish acts as an intermediate or paratenic host of this digenean in Brazil.

Contribution to the study of the digenean trematode Clinostomum complanatum parasite of the Nile Tilapia (Oreochromis niloticus) in breeding basins in southern Mauritania

“…Figure 3: Sampling of parasites from their locations on fish: oral cavities or gills Clinostomum infestation increases with host size, suggesting a cumulative process (Kalantan et al, 1987). The comparison of morphological, anatomical and biometric criteria and the comparison with other parasites found in other regions in this species of fish or in other neighboring species (Khan et al 2018;Ribeiro et al, 2019) allowed us to classify this digenean trematode parasite of Tilapia, in the species Clinostomum complanatum (Rudolphi, 1814).…”